Source code for PIL.MspImagePlugin

#
# The Python Imaging Library.
#
# MSP file handling
#
# This is the format used by the Paint program in Windows 1 and 2.
#
# History:
#       95-09-05 fl     Created
#       97-01-03 fl     Read/write MSP images
#       17-02-21 es     Fixed RLE interpretation
#
# Copyright (c) Secret Labs AB 1997.
# Copyright (c) Fredrik Lundh 1995-97.
# Copyright (c) Eric Soroos 2017.
#
# See the README file for information on usage and redistribution.
#
# More info on this format: https://archive.org/details/gg243631
# Page 313:
# Figure 205. Windows Paint Version 1: "DanM" Format
# Figure 206. Windows Paint Version 2: "LinS" Format. Used in Windows V2.03
#
# See also: http://www.fileformat.info/format/mspaint/egff.htm

from . import Image, ImageFile
from ._binary import i16le as i16, o16le as o16, i8
import struct
import io

__version__ = "0.1"


#
# read MSP files


def _accept(prefix):
    return prefix[:4] in [b"DanM", b"LinS"]


##
# Image plugin for Windows MSP images.  This plugin supports both
# uncompressed (Windows 1.0).

[docs]class MspImageFile(ImageFile.ImageFile): format = "MSP" format_description = "Windows Paint" def _open(self): # Header s = self.fp.read(32) if s[:4] not in [b"DanM", b"LinS"]: raise SyntaxError("not an MSP file") # Header checksum checksum = 0 for i in range(0, 32, 2): checksum = checksum ^ i16(s[i:i+2]) if checksum != 0: raise SyntaxError("bad MSP checksum") self.mode = "1" self._size = i16(s[4:]), i16(s[6:]) if s[:4] == b"DanM": self.tile = [("raw", (0, 0)+self.size, 32, ("1", 0, 1))] else: self.tile = [("MSP", (0, 0)+self.size, 32, None)]
[docs]class MspDecoder(ImageFile.PyDecoder): # The algo for the MSP decoder is from # http://www.fileformat.info/format/mspaint/egff.htm # cc-by-attribution -- That page references is taken from the # Encyclopedia of Graphics File Formats and is licensed by # O'Reilly under the Creative Common/Attribution license # # For RLE encoded files, the 32byte header is followed by a scan # line map, encoded as one 16bit word of encoded byte length per # line. # # NOTE: the encoded length of the line can be 0. This was not # handled in the previous version of this encoder, and there's no # mention of how to handle it in the documentation. From the few # examples I've seen, I've assumed that it is a fill of the # background color, in this case, white. # # # Pseudocode of the decoder: # Read a BYTE value as the RunType # If the RunType value is zero # Read next byte as the RunCount # Read the next byte as the RunValue # Write the RunValue byte RunCount times # If the RunType value is non-zero # Use this value as the RunCount # Read and write the next RunCount bytes literally # # e.g.: # 0x00 03 ff 05 00 01 02 03 04 # would yield the bytes: # 0xff ff ff 00 01 02 03 04 # # which are then interpreted as a bit packed mode '1' image _pulls_fd = True
[docs] def decode(self, buffer): img = io.BytesIO() blank_line = bytearray((0xff,)*((self.state.xsize+7)//8)) try: self.fd.seek(32) rowmap = struct.unpack_from("<%dH" % (self.state.ysize), self.fd.read(self.state.ysize*2)) except struct.error: raise IOError("Truncated MSP file in row map") for x, rowlen in enumerate(rowmap): try: if rowlen == 0: img.write(blank_line) continue row = self.fd.read(rowlen) if len(row) != rowlen: raise IOError( "Truncated MSP file, expected %d bytes on row %s", (rowlen, x)) idx = 0 while idx < rowlen: runtype = i8(row[idx]) idx += 1 if runtype == 0: (runcount, runval) = struct.unpack_from("Bc", row, idx) img.write(runval * runcount) idx += 2 else: runcount = runtype img.write(row[idx:idx+runcount]) idx += runcount except struct.error: raise IOError("Corrupted MSP file in row %d" % x) self.set_as_raw(img.getvalue(), ("1", 0, 1)) return 0, 0
Image.register_decoder('MSP', MspDecoder) # # write MSP files (uncompressed only) def _save(im, fp, filename): if im.mode != "1": raise IOError("cannot write mode %s as MSP" % im.mode) # create MSP header header = [0] * 16 header[0], header[1] = i16(b"Da"), i16(b"nM") # version 1 header[2], header[3] = im.size header[4], header[5] = 1, 1 header[6], header[7] = 1, 1 header[8], header[9] = im.size checksum = 0 for h in header: checksum = checksum ^ h header[12] = checksum # FIXME: is this the right field? # header for h in header: fp.write(o16(h)) # image body ImageFile._save(im, fp, [("raw", (0, 0)+im.size, 32, ("1", 0, 1))]) # # registry Image.register_open(MspImageFile.format, MspImageFile, _accept) Image.register_save(MspImageFile.format, _save) Image.register_extension(MspImageFile.format, ".msp")